A Comparison of the Biological Characteristics of EV71 C4 Subtypes from Different Epidemic Strains

The comparative analysis of the biological characterization and the genetic background study of EV71 circulating strains is commonly recognized as basic work necessary for development of an effective EV71 vaccine. In this study, we sequenced five EV71 circulating strains, isolated from Fuyang, Hefei, Kunming and Shenzhen city of China and named them FY-23, FY-22, H44, K9 and S1 respectively. The sequence alignment demonstrated their genotypes be C4. The genetic distance of the VP1 gene from these isolates suggested that they were highly co-related with genetic identity similar to other previously reported EV71 strains in China. Additionally, these strains were identified to display some obvious proliferation dynamics and plaque morphology when propagated in Vero cells. However, a distinctive difference in pathogenic ability in neonatal mice was found. Some differences in cross neutralization test & immunogenic analysis were also found. All these results are related to the biological characterization of circulating EV71 strains in China and aid in the development of an EV71 vaccine in the future.

Protective efficacy of an H5/H7 trivalent inactivated vaccine(H5-Re13,H5-Re14, and H7-Re4 strains) in chickens, ducks, and geese against newly detected H5N1, H5N6, H5N8, and H7N9 viruses

Some H5 viruses isolated in poultry or wild birds between 2020 and 2021 were found to be antigenically different from the vaccine strains(H5-Re11 and H5-Re12) used in China. In this study, we generated three new recombinant vaccine seed viruses by using reverse genetics and used them for vaccine production. The vaccine strain H5-Re13 contains the hemagglutinin(HA) and neuraminidase(NA) genes of an H5 N6 virus that bears the clade 2.3.4.4 h HA gene, H5-Re14 contains the HA and NA genes of an H5 N8 virus that bears the clade 2.3.4.4 b HA gene, and H7-Re4 contains the HA and NA genes of H7 N9 virus detected in 2021. We evaluated the protective efficacy of the novel H5/H7 trivalent inactivated vaccine in chickens, ducks, and geese. The inactivated vaccine was immunogenic and induced substantial antibody responses in the birds tested. Three weeks after vaccination, chickens were challenged with five different viruses detected in 2020 and 2021: three viruses(an H5 N1 virus, an H5 N6 virus, and an H5 N8 virus) bearing the clade 2.3.4.4 b HA gene, an H5 N6 virus bearing the clade 2.3.4.4 h HA gene, and an H7 N9 virus. All of the control birds shed high titers of virus and died within 4 days post-challenge, whereas the vaccinated chickens were completely protected from these viruses. Similar protective efficacy against H5 viruses bearing the clade 2.3.4.4 h or 2.3.4.4 b HA gene was observed in ducks and geese. Our study indicates that the newly updated H5/H7 vaccine can provide solid protection against the H5 and H7 N9 viruses that are currently circulating in nature.

Misfit strains inducing voltage decay in LiMn_(y)Fe_(1-y)PO_(4)/C

LiMn_(y)Fe_(1-y)PO_(4) is considered a promising cathode material for next-generation lithium-ion batteries(LIBs) due to its high energy density and low cost. Its energy density degradation is often ascribed to the capacity loss during cycling. However, in this study, we find that the energy density degradation mainly roots in voltage decay. We have synthesized a series of LiMn_(y)Fe_(1-y)PO_(4) /C(0.5 ≤ y ≤ 0.8) and find this voltage decay is correlated with the Mn content. A high amount Mn leads to a heavier voltage decay.In-situ X-ray diffraction(XRD) and high-resolution transmission electron microscopy(HRTEM) reveal the nature of this effect, which show a mismatch along the b-axis of-2.68%(charge) and +3.4%(discharge), a volume misfit of-4.41%(charge) and +4.54%(discharge) between Li_(x)Mn_(y)Fe_(1-y)PO_(4) and Mn_(y)Fe_(1-y)PO_(4) during phase transitions. The resultant misfit strains during Li+insertion compared to extraction result in structural degradations, such as amorphization and impurity(Mn F3) accumulation after cycling. The voltage decay can be alleviated by kinetic relaxations and recovered by a wild reannealing. This work demonstrates effective strategies to improve the energy density and cycling performance of LiMn_(y)Fe_(1-y)PO_(4) /C,providing good references for other LIB cathodes, such as the Li-rich cathodes.

四川地区YRY-4型钻孔应变观测资料可靠性分析

通过分析钻孔应变观测资料的干扰因素,发现四川地区YRY-4型钻孔应变受季节性降雨、钻孔水位和河水位涨落影响显著。采用钻孔应变自洽检验对钻孔应变仪观测数据进行自检,发现各台应变校正相关系数均大于0.9,说明四川地区YRY-4型应变观测资料的整体质量较高,可以用于区域地震预测和地震科学研究。

二维MoSi_(2)N_(4)/WSe_(2)异质结的第一性原理研究

实验上新合成的MoSi_(2)N_(4)(MSN)由于其独特的七原子层结构和电子特性引起了人们的广泛关注.本文搭建了一种由二维MSN与二维WSe_(2)(WS)垂直堆垛而成的二维MSN/WS异质结并基于第一性原理计算对其电子性质进行了计算,其表现出直接间隙半导体和I型能带排列的特性,具有1.46 eV的带隙.在异质结界面处存在一个由电荷耗尽层MSN指向电荷积累层WS微弱的内建电场.最后,通过施加双轴应变对二维MSN/WS异质结进行调控.发现在正双轴应变的作用下,MSN/WS异质结保持了原来直接带隙半导体和I型能带排列特性;在负双轴应变作用下,MSN/WS异质结由原来的直接带隙半导体转变为间接带隙半导体,当施加的负双轴应变达到-6%与-8%时,I型能带排列转变为Ⅱ型能带排列.

PRRSV BJ-4株ORF5基因的原核表达与重组蛋白的纯化

为成功表达猪繁殖与综合征病毒(PRRSV)结构蛋白GP5,通过PCR方法从重组质粒pGEM ORF5扩增得到缺失N端疏水序列的基因片段dORF5(deletingORF5)。将dORF5克隆至原核高效表达载体pGEX 4T 2,在E.coliBL21细胞中成功表达了重组蛋白GST dORF5,表达产物以包涵体的形式存在,表达量为20 8%。Western Blot结果表明重组蛋白可被PRRSV阳性血清所识别。利用融合肽进行亲和层析得到高纯度的重组蛋白,为进一步研究PRRS病毒结构蛋白的结构和功能奠定了基础。

BJ-4直线加速器低压电源故障的检修及工作环境的改进

自动频率控制系统 (AFC)和操作控制台低压电源部分 ,在工作中 ,散热环境不佳 ,一些发热的元件经常烧坏。本文就此原因作了改进 。

Probiotic yeasts: Anti-inflammatory potential of various non-pathogenic strains in experimental colitis in mice

AIM: To evaluate the in vitro immunomodulation capacity of various non-pathogenic yeast strains and to investigate the ability of some of these food grade yeasts to prevent experimental colitis in mice.METHODS: In vitro immunomodulation was assessed by measuring cytokines [interleukin (IL)-12p70,IL-10,tumor necrosis factor and interferon γ] released by human peripheral blood mononuclear cells after 24 h stimulation with 6 live yeast strains (Saccharomyces ssp.) and with bacterial reference strains.A murine model of acute 2-4-6-trinitrobenzene sulfonic acid (TNBS)-colitis was next used to evaluate the distinct prophylactic protective capacities of three yeast strains compared with the performance of prednisolone treatment.RESULTS: The six yeast strains all showed similar non-discriminating anti-inflammatory potential when tested on immunocompetent cells in vitro .However,although they exhibited similar colonization patterns in vivo ,some yeast strains showed significant anti-inflammatory activities in the TNBS-induced colitis model,whereas others had weaker or no preventive effect at all,as evidenced by colitis markers (body-weight loss,macroscopic and histological scores,myeloperoxidase activities and blood inflammatory markers).CONCLUSION: A careful selection of strains is required among the biodiversity of yeasts for specific clinical studies,including applications in inflammatory bowel disease and other therapeutic uses.

Biodegradation of Phenol and 4-Chlorophenol by the Mutant Strain CTM 2

The biodegradations of phenol and 4-chlorophenol （4-cp） were studied using the mutant strain CTM 2 obtained by the He-Ne laser irradiation on wild-type Candida tropicalis. The results showed that the capacity of the CTM 2 to biodegrade 4-cp was increased up to 400 mg·L^-1 within 59.5 h. In the dual-substrate biodegradation both velocity and capacity of the CTM 2 to degrade 4-cp increased with low-concentration phenol. A totalof 400 mg·L^-1 4-cp was completely degraded within 50.＇5 h in thepresence of 300 mg·L^-1 phenol. The maximum 4：cp biodegegradation could reach 440 mg·L^1 with 120 mg·L^1 phenol. Low-concentration 4-cp caused great inhibition on the CTM 2 to degrade phenol. In addition, the kinetic behaviors were described using the kinetic model proposed in this lab.

Variation effect of strain rate on microstructure in isothermal compression of Ti-6Al-4V alloy

Isothermal compression of the Ti-6Al-4V alloy at the deformation temperatures of 950 and 980℃,height reductions of 30% and 60%,and strain rates of 0.001,0.010,0.100 and 1.000 s-1 was conducted,wherein the variations of microstructure with strain rate were investigated.The experimental results showed that the variation of the microstructure with the strain rate under one condition was significantly different from that under another condition,which meaned that the interaction between the processing parameters was great.The optimization of the strain rate under one condition was not suitable for another condition.Therefore,selecting the forging equipment and optimizing the strain rate should be based on simultaneously considering the deformation temperature and height reduction.

Mechanical characterization of Mg-B4C nanocomposite fabricated at different strain rates

Magnesium has wide application in industry.The main purpose of this investigation was to improve the properties of magnesium by reinforcing it using B4C nanoparticles.The reinforced nanocomposites were fabricated using a powder compaction technique for 0,1.5vol%,3vol%,5vol%,and 10vol% of B4C.Powder compaction was conducted using a split Hopkinson bar(SHB),drop hammer(DH),and Instron to reach different compaction loading rates.The compressive stress–strain curves of the samples were captured from quasi-static and dynamic tests carried out using an Instron and split Hopkinson pressure bar,respectively.Results revealed that,to achieve the highest improvement in ultimate strength,the contents of B4C were 1.5vol%,3vol%,and 3vol% for Instron,DH,and SHB,respectively.These results also indicated that the effect of compaction type on the quasi-static strength of the samples was not as significant,although its effect on the dynamic strength of the samples was remarkable.The improvement in ultimate strength obtained from the quasi-static stress–strain curves of the samples(compared to pure Mg)varied from 9.9% for DH to 24% for SHB.The dynamic strength of the samples was improved(with respect to pure Mg)by 73%,116%,and 141%for the specimens compacted by Instron,DH,and SHB,respectively.The improvement in strength was believed to be due to strengthening mechanisms,friction,adiabatic heating,and shock waves.

Effect of strain rate difference between inside and outside groove in M-K model on prediction of forming limit curve of Ti6Al4V at elevated temperatures

The influence of initial groove angle on strain rate inside and outside groove of Ti6Al4V alloy was investigated.Based on the evolution of strain rate inside and outside groove,the effect of strain rate difference on the evolution of normal stress and effective stress inside and outside groove was also analyzed.The results show that when linear loading path changes from uniaxial tension to equi-biaxial tension,the initial groove angle plays a weaker role in the evolution of strain rate in the M-K model.Due to the constraint of force equilibrium between inside and outside groove,the strain rate difference makes the normal stress inside groove firstly decrease and then increase during calculation,which makes the prediction algorithm of forming limit convergent at elevated temperature.The decrease of normal stress inside groove is mainly caused by high temperature softening effect and the rotation of groove,while the increase of normal stress inside groove is mainly due to strain rate hardening effect.

Isolation and Identification of Two Antibacterial Agents from <i>Chromolaena odorata</i>L. Active against Four Diarrheal Strains

Chromolaena odorata L (Asteraceae) is a bad invasive plant, found in the humid tropics and sub-tropics worldwide. It is used against dysentery, diarrhea, malaria, wound healing, headache and toothache in traditional medicine. In the present study, we investigated the antibacterial activities of different leaves extracts of Chromolaena odorata L. (cyclohexane, dichloromethane, ethyl acetate and butanol) against four clinical diarrheal strains (Klebsiella oxytoca, Salmonella enterica, Shigella sonnei and Vibrio cholera). We demonstrated that C. odorata leaves extracts show an antibacterial activity between 0.156 and 1.25 mg/mL. Bioassay-guided chromatography by bioautography with iodonitrotetrazolium-based colorimetric assay allowed the isolation and identification of two active compounds. After the combination of RP-HPLC, mass spectrometry analysis, 1D and 2D-NMR spectroscopy, we isolated and characterized two active molecules corresponding to 3’,4’,5,6,7-Pentamethoxyflavone (Sinensetin) and4’,5,6,7-Tetramethoxyflavone (Scutellareintetramethyl ether).

Modulation of Schottky barrier in XSi_(2)N_(4)/graphene(X=Mo and W)heterojunctions by biaxial strain

Reducing the Schottky barrier height(SBH)and even achieving the transition from Schottky contacts to Ohmic contacts are key challenges of achieving high energy efficiency and high-performance power devices.In this paper,the modulation effects of biaxial strain on the electronic properties and Schottky barrier of Mo Si_(2)N_(4)(MSN)/graphene and WSi_(2)N_(4)(WSN)/graphene heterojunctions are examined by using first principles calculations.After the construction of heterojunctions,the electronic structures of MSN,WSN,and graphene are well preserved.Herein,we show that by applying suitable external strain to a heterojunction stacked by MSN or WSN—an emerging two-dimensional(2D)semiconductor family with excellent mechanical properties—and graphene,the heterojunction can be transformed from Schottky ptype contacts into n-type contacts,even highly efficient Ohmic contacts,making it of critical importance to unleash the tremendous potentials of graphene-based van der Waals(vd W)heterojunctions.Not only are these findings invaluable for designing high-performance graphene-based electronic devices,but also they provide an effective route to realizing dynamic switching either between n-type and p-type Schottky contacts,or between Schottky contacts and Ohmic contacts.

Plastic Flow Modeling of Ti-5 Al-2 Sn-2 Zr-4 Mo-4 Cr Alloy at Elevated Temperatures and High Strain Rates

The true stress-sWain relationships of Ti-5A1-2Sn-2Zr-4Mo-4Cr（TC17） alloy with a wide range of strain rates were investigated by tmiaxial quasi-static and dynamic compression tests, respectively. Quasi- static compression tests were carried out with Instron 8874 test machine, while dynamic compression tests were performed with the split Hopkinson pressure bar （SHPB） which was installed with heating device and synchro- assembly system. The dynamic mechanical behaviors tests of TC17 were carded out from room temperature to 800 ℃ at intervals of 200 ℃ and at high sWain rates （5 500-1 9200 s-l）. The stress-strain curves considering temperature-sWain rate coupling actions were obtained. The Johnson-Cook constitutive model was developed through data fitting of the stress-sWain curves. The material constants in the developed constitutive model can be determined using isothermal and adiabatic stress-strain curves at different strain rates. The Johnson-Cook constitutive model provided satisfied prediction of the plastic flow stress for TC17 alloy.